The preleukemic syndrome. II. Cytogenetic findings

Area of Science:

• Hematology
• Cytogenetics
• Oncology

Background:

• Preleukemic syndrome, also known as myelodysplastic syndromes (MDS), represents a heterogeneous group of clonal hematopoietic stem cell disorders.
• These disorders are characterized by ineffective hematopoiesis and a significant risk of transformation into acute myeloid leukemia (AML).
• Cytogenetic abnormalities in the bone marrow are known prognostic markers in MDS.

Purpose of the Study:

• To investigate the frequency and types of chromosome aberrations in patients with preleukemic syndrome during both the preleukemic phase and after blastic transformation.
• To compare the cytogenetic findings with those in published series of patients with acute non-lymphoblastic leukemia (ANLL).
• To explore the presence of abnormal cell lines in peripheral blood lymphocytes.

Main Methods:

• Bone marrow chromosome studies were performed on 88 patients during the preleukemic phase and 10 after blastic transformation.
• Chromosome analysis was conducted both with and without banding techniques.
• Peripheral blood lymphocyte cultures stimulated with phytohemagglutinin (PHA) were analyzed for abnormal cell lines.

Main Results:

• Chromosome abnormalities were detected in 24% of cases studied without banding and 50% with banding, a significant increase in yield.
• Commonly observed aberrations included -Y, +8, del 5q, and del F or del 20q, frequently seen in myeloproliferative disorders.
• After blastic transformation, 15 out of 19 patients showed more complex abnormalities.
• Abnormal cell lines with identical chromosome abnormalities were found in PHA-stimulated blood cultures of 9 patients.

Conclusions:

• Banding techniques significantly enhance the detection of chromosome aberrations in preleukemic syndrome.
• The observed cytogenetic abnormalities are consistent with myeloproliferative disorders and suggest a potential link to leukemic transformation.
• The presence of abnormal lymphocyte subpopulations may originate from the same pluripotent stem cell as the leukemic cells.